There is a first known miniature coaxial connector, as disclosed in Japanese Unexamined Patent Publication No. 9(1997)-120870 (FIG. 1C). This connector comprises an inner contact, which is connected to an inner conductor of a coaxial cable by soldering and an outer contact, which is connected to an outer conductor of the coaxial cable by crimping.
There is a second conventional miniature coaxial connector, as disclosed in Japanese Unexamined Utility Model Publication No. 5(1993)-045962 (FIG. 2). This connector comprises an inner contact, which is connected to an inner conductor of a coaxial cable by crush crimping and an outer contact, which is connected to an outer conductor of the coaxial cable by crush crimping. The portion at which the coaxial cable and the inner contact are connected is covered by a cylindrical insulative housing having a substantially uniform thickness.
There is a third known coaxial connector, as disclosed in U.S. Pat. No. 6,015,315 (FIG. 2, FIG. 4). This connector comprises an inner contact, which is soldered onto an inner conductor of a coaxial cable and a cylindrical insulator that covers the periphery of a central connection portion of the inner contact Ribs that extend in the longitudinal direction of the insulator are provided on the inner surface of the insulator, separated in the circumferential direction thereof. The ribs provide spaces between the insulator and the inner contact, thereby increasing characteristic impedance.
In the first known miniature coaxial connector, the inner contact is connected to the inner conductor of the coaxial cable by soldering. Because the amount of solder used varies depending on the person who performs soldering, fluctuations occur in the outer dimensions of the soldered portion. In cases in which signal propagating frequencies are high, the fluctuations may cause characteristic impedance to shift from desired values. In addition, solder utilizes lead, which is not favorable from an ecological viewpoint during disposal thereof
In the second known coaxial connector, the inner contact and the outer contact are connected to the coaxial cable by crimping. Because the second coaxial connector does not utilize lead, it is favorable from the ecological viewpoint However, impedance matching in the vicinity of the crimped portion, where the inner contact and the coaxial cable are connected, is not taken into consideration.
The third known coaxial connector has two problems. The first problem is that it utilizes lead, which is not favorable from the ecological viewpoint. The second is that impedance is not uniform along the circumference of the insulator.